Today we live in the midst of an information explosion. The rapid development of computing and telecommunications technologies in the 1980's has served as a gateway to an entirely new world. In spite of the ever increasing capacity for storing and retrieving information, demand for that capacity seems to increase in lockstep. The growth of personal computing and personal communications systems will further fuel this need well into the twenty first century. As the demand for information capacity grows, so does the need to transport that data. Computer designers no longer have the luxury of treating the interconnect as an afterthought to their computer design process.
Presently, fiber optics industries have established market share in telecommunications and are beginning to penetrate the Local Area Network (LAN) markets. However, these industries still carry the high cost structure associated with telecommunications solutions. This high cost structure has prevented the successful penetration of optics into the very high volume interconnect markets associated with the desktop computer industry.
The underlying pattern of the desktop market today is a respectable growth rate in a market dominated by copper cable operating with limited bandwidth capability. As computers become more powerful the demand for inexpensive high performance interconnects will increase. For example, it is expected that when high resolution monitors reach the market in 1-2 years, the demand for an inexpensive, high performance interconnect will rise significantly.
Fiber optic technology was, at its inception in the late 1960's, faced with the challenge of penetrating the electronics marketplace. When optical fiber loss was dramatically reduced to less than 1 db/Km in the late 1970's, the opportunity to begin to replace costly copper transmission lines with a single optical fiber emerged. Transmission of many telephone calls over long unrepeated distances could ultimately lead to significant reduction in a system's cost per channel-mile. Because telecommunications systems costs are driven largely by cable cost, the fiber solution could be implemented without regard to the cost of the electro-optic interfaces. A major consequence of this situation is the very high cost of manufacturing these interfaces, even today.
The introduction of fiber optic communications into computer systems has lagged far behind the usage fiber optics have seen in the telecommunications industries. This should not be surprising, since the cost-per channel mile figure of merit which originally drove fiber optics is not as important in the computer industry. Instead, computer designs are driven by the need to produce low cost, high performance information processing systems and equipment. Hardware-related issues are mostly packaging and interconnect related. While these issues have always held high priority for computer equipment manufacturers, only recently have they taken a slightly different flavor. With the speed of microprocessors now rapidly being pushed into and beyond the 100 Mb/s region, it is becoming very difficult to separate the circuit design-fabrication issues from the packaging-interconnect issues. Instead, packages and their interconnections are an inseparable part of circuits.
Computer processing speeds have enjoyed a steady and impressive growth during the last decade, and are expected to continue that trend even though significant technical problems are involved. As computers become more complex, additional interconnect complexity follows, leading to more constrained degrees of freedom in system design. Questions are routinely asked if for example, back-planes or motherboards are really necessary, and at what cost-performance do they make sense. Issues like system partitioning which demands innovative design for the extra degree of freedom it generates must be solved.